/*
 * gcc -o demo ketkey2.c
 * ./demo
 */

#include <stdio.h>
#include <stdlib.h>

#define TTY_PATH            "/dev/tty"
#define STTY_US             "stty raw -echo -F "
#define STTY_DEF            "stty -raw echo -F "

int get_char();

int get_char()
{
    fd_set rfds;
    struct timeval tv;
    int ch = 0;

    FD_ZERO(&rfds);
    FD_SET(0, &rfds);
    tv.tv_sec = 0;
    tv.tv_usec = 10; //设置等待超时时间

    //检测键盘是否有输入
    if (select(1, &rfds, NULL, NULL, &tv) > 0){
        ch = getchar(); 
    }
    return ch;
}

int main(){
    int ch = 0;
    system(STTY_US TTY_PATH);

    while(1){
        ch = get_char();
        if(ch != 0){
            printf("\n%x\n\r",ch);
        }
        if(ch == 3){
            system(STTY_DEF TTY_PATH);
            return 0;
        }         
    }
}
